☣️ UN 3258 • CLASS 9
Elevated temperature solid, n.o.s., at or above 240°C (464°F)
Placard: Miscellaneous. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
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⚠️ This page is a quick-reference aid. For real incidents: stage upwind, isolate, deny entry, request Hazmat early, and consult the current ERG + SOP/SOG.
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Quick details
UN 3258
Class: 9
Placard type: Miscellaneous
ERG: Guide 171 (check current ERG)
Isolation: ERG 171: isolate spill or leak area immediately for at least 25-50m in all directions; if tank/rail car is involved in fire, isolate 800m in all directions
Chemical & Response Details
| Also known as | Hot solid materialMolten solidElevated temperature materialHigh temperature solid n.o.s. |
| Appearance | Variable solid material transported at temperatures at or above 240°C (464°F). Physical appearance depends on specific substance; typically appears as hot or molten solid material that may glow or emit heat. |
| Flash Point | Not applicable (elevated temperature solid) |
| Boiling Point | Variable depending on specific material; transported above 240°C (464°F) |
| Vapor Density | Not applicable (solid material) |
| Water Reactivity | Variable; some materials may react with water creating steam or violent reactions when hot. Avoid water contact with hot material. |
| Extinguishing | Dry sand, dry chemical, or soda ash for small fires; allow large fires to burn; do not use water on hot material |
| PPE | ⚠️ Structural firefighters protective clothing provides limited protection; heat-resistant clothing recommended; SCBA required; maintain safe distance due to extreme heat |
| Isolation | ERG 171: isolate spill or leak area immediately for at least 25-50m in all directions; if tank/rail car is involved in fire, isolate 800m in all directions |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Common hazards (high level)
- Some may burn but none ignite readily.
- Containers may explode when heated.
- Some may be transported hot.
- For UN3508, Capacitor, asymmetric, be aware of possible short circuiting as this product is transported
- Polymeric beads, expandable (UN2211) may evolve flammable vapours.
- Inhalation of material may be harmful.
- Contact may cause burns to skin and eyes.
- Inhalation of Asbestos dust may have a damaging effect on the lungs.
First actions (field-minded)
- CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper
- Keep unauthorized personnel away.
- Stay upwind, uphill and/or upstream.
- Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters
- For highlighted materials: see Table 1 - Initial Isolation and Protective Action Distances.
- For non-highlighted materials: increase the immediate precautionary measure distance, in the downwind
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UN 3258 — Elevated temperature solid, n.o.s., at o HAZMAT RADIO NOTE — UN 3258
Product: Elevated temperature solid, n.o.s., at or above 240°C (464°F)
Class 9 / Miscellaneous / ERG 171
PPE: Structural firefighters protective clothing provides limited protection; heat-resistant clothing recommended; SCBA required; maintain safe distance due to extreme heat
ISOLATION: ERG 171: isolate spill or leak area immediately for at least 25-50m in all directions; if tank/rail car is involved in fire, isolate 800m in all directions
ACTION: Stage upwind · Isolate · Deny entry · Request HazmatRADIO
Use for: Quick radio or face-to-face size-up. Short, structured, field-ready.
=== IC HAZMAT BRIEFING ===
UN 3258 — Elevated temperature solid, n.o.s., at or above 240°C (464°F)
Class: 9 | Placard: Miscellaneous | ERG Guide: 171
Appearance: Variable solid material transported at temperatures at or above 240°C (464°F). Physical appearance depends on specific substance; typically appears as hot or molten solid material that may glow or emit heat.
Water Reactivity: Variable; some materials may react with water creating steam or violent reactions when hot. Avoid water contact with hot material.
Extinguishing: Dry sand, dry chemical, or soda ash for small fires; allow large fires to burn; do not use water on hot material
PPE: Structural firefighters protective clothing provides limited protection; heat-resistant clothing recommended; SCBA required; maintain safe distance due to extreme heat
Isolation: ERG 171: isolate spill or leak area immediately for at least 25-50m in all directions; if tank/rail car is involved in fire, isolate 800m in all directions
— Key Hazards —
• Some may burn but none ignite readily.
• Containers may explode when heated.
• Some may be transported hot.
— First Actions —
• CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper
• Keep unauthorized personnel away.
• Stay upwind, uphill and/or upstream.
• Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters
SOURCE: allfirefighter.com/hazmat/un/3258 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN3258 Elevated temperature solid, n.o.s., at or above 240°C (464°F) Cls9 ERG171 | allfirefighter.com/hazmat/un/3258SMS / 160 CHAR
Use for: Quick text to command or incoming units. Fits in a single SMS. Includes link to full page.
⚠️ Quick-reference only. Always use current ERG + SOP/SOG for incident-specific actions. Page: https://allfirefighter.com/hazmat/un/3258
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FAQ
Some may burn but none ignite readily. Containers may explode when heated. Some may be transported hot. For UN3508, Capacitor, asymmetric, be aware of possible short circuiting as this product is transported Polymeric beads, expandable (UN2211) may evolve flammable vapours. Inhalation of material may be harmful. Contact may cause burns to skin and eyes. Inhalation of Asbestos dust may have a damaging effect on the lungs.
CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper Keep unauthorized personnel away. Stay upwind, uphill and/or upstream.
Structural firefighters protective clothing provides limited protection; heat-resistant clothing recommended; SCBA required; maintain safe distance due to extreme heat
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 171 and your department SOP/SOG for incident-specific protective actions.
Sources (high level): DOT/PHMSA marking & class concepts + ERG usage principles. This page does not reproduce ERG guide text—always consult the current ERG for incident-specific protective actions.